Pure substances can be separated by physical means.
A. True
B. False

Agraduated cylinder contains 63.0 ml of water. a piece of gold, which has a density of 19.3 g/ cm3, is added to the water and the volume goes up to 64.5 ml. calculate the mass in grams of the gold that was added to the water. explain how you got your answer.

What component of earth’s atmosphere exists entirely as a result of photosynthesis?

Sound travels slower in colder air that it does in warmer air. make a claim about the effect of air temperature on the speed of sound. support your claim with evidence